Search results for: surface water-groundwater interaction

Authors: M. Manohari, Himanshu Gupta, S. Priyadharshini, R. Santhanam, S. Chandrasekaran, B. Venkatraman

Abstract:

Injection is one of the potential routes of intake in a radioactive facility. The internal dose due to this intake is monitored at the radiation emergency medical centre, IGCAR using a portable planar HPGe detector. The contaminated wound may be having different shapes. In a reprocessing potential of wound contamination with actinide is more. Efficiency is one of the input parameters for estimation of internal dose. Estimating these efficiencies experimentally would be tedious and cumbersome. Numerical estimation can be a supplement to experiment. As an initial step in this study 241Am contamination of different shapes are studied. In this study portable planar HPGe detector was modeled using Monte Carlo code FLUKA and the effect of different parameters like distance of the contamination from the detector, radius of the circular contamination were studied. Efficiency values for point and surface contamination located at different distances were estimated. The effect of efficiency on the radius of the surface source was more predominant when the source is at 1 cm distance compared to when the source to detector distance is 10 cm. At 1 cm the efficiency decreased quadratically as the radius increased and at 10 cm it decreased linearly. The point source efficiency varied exponentially with source to detector distance.

Keywords: Planar HPGe, efficiency value, injection, surface source

Procedia PDF Downloads 40

Authors: Rahul R. Gurpude, Pallvita Yadav, Amrut Mulay

Abstract:

In recent years, there has been a growing focus on advanced manufacturing processes, and one such emerging process is wire electric discharge machining (WEDM). WEDM is a precision machining process specifically designed for cutting electrically conductive materials with exceptional accuracy. It achieves material removal from the workpiece metal through spark erosion facilitated by electricity. Initially developed as a method for precision machining of hard materials, WEDM has witnessed significant advancements in recent times, with numerous studies and techniques based on electrical discharge phenomena being proposed. These research efforts and methods in the field of ED encompass a wide range of applications, including mirror-like finish machining, surface modification of mold dies, machining of insulating materials, and manufacturing of micro products. WEDM has particularly found extensive usage in the high-precision machining of complex workpieces that possess varying hardness and intricate shapes. During the cutting process, a wire with a diameter ranging from 0.18mm is employed. The evaluation of EDM performance typically revolves around two critical factors: material removal rate (MRR) and surface roughness (SR). To comprehensively assess the impact of machining parameters on the quality characteristics of EDM, an Analysis of Variance (ANOVA) was conducted. This statistical analysis aimed to determine the significance of various machining parameters and their relative contributions in controlling the response of the EDM process. By undertaking this analysis, optimal levels of machining parameters were identified to achieve desirable material removal rates and surface roughness.

Keywords: WEDM, MRR, optimization, surface roughness

Procedia PDF Downloads 73

Authors: Satpal Singh, Subhash Chander

Abstract:

An experimental study has been conducted to evaluate the thermal performance of the CNG/air dual flame impinging normally on to a flat surface. The stability limits for the dual flame under both impinging and free conditions have been evaluated to select experimental operating range. Dual flame shape and structure have been explained with direct flame image and schematic diagram indicating modification in recirculation zone in presence of inner flame. Effects of various operating parameters like H/Dh, Re(o), Φ(o), and θ(o) on heat transfer characteristics have been discussed. Inner non-swirling flame Reynolds number (Re(i)) and equivalence ratio (Φ(i)) were kept constant. Heating patterns in the impingement region around the stagnation point have been altered significantly with change in the values of H/Dh, Re(o), Φ(o), and θ(o). The axial flow of inner flame has been notably effected with increase in Re(o). Heating was most favorable near stoichiometeric conditions of the outer swirling flame. However, the effect of change in swirl intensity (expressed in terms of θ(o)) on overall heat transfer efficiency was not as significant as in the case of other parameters. It has been inferred that best performance (higher uniformity and efficiency) of the dual flame impinging on a flat surface can be achieved at moderate value of separation distance (H/Dh of 2-3) and outer swirling flame Reynolds number (Re(o) of 7000-9000) under stoichiometeric conditions.

Keywords: dual flame, heat transfer, impingement, swirling insert, transmission efficiency

Procedia PDF Downloads 296

Authors: Chunhong Zhao

Abstract:

Remotely sensed land surface temperature (LST) is vital to understand the land-atmosphere energy balance, hydrological cycle, and thus is widely used to describe the urban heat island (UHI) phenomenon. However, due to technical constraints, satellite thermal sensors are unable to provide LST measurement with both high spatial and high temporal resolution. Despite different downscaling techniques and algorithms to generate high spatiotemporal resolution LST. Four major metropolitan areas in Texas, USA: Dallas-Fort Worth, Houston, San Antonio, and Austin all demonstrate UHI effects. Different cities are expected to have varying SUHI effect during the urban development trajectory. With the help of the Landsat, ASTER, and MODIS archives, this study focuses on the spatial patterns of UHIs and the seasonal and annual variation of these metropolitan areas. With Gaussian model, and Local Indicators of Spatial Autocorrelations (LISA), as well as data fusion methods, this study identifies the hotspots and the trajectory of the UHI phenomenon of the four cities. By making comparison analysis, the result can help to alleviate the advent effect of UHI and formulate rational urban planning in the long run.

Keywords: spatiotemporal analysis, land surface temperature, urban heat island evaluation, metropolitan areas of Texas, USA

Procedia PDF Downloads 413

Authors: Bingjie Wang, Su-Yeon Kwon, Ik-Joong Kang

Abstract:

A Surface-enhanced Raman Scattering (SERS) as the principle for enhancing Raman scattering by molecules adsorbed on rough metal surfaces or by nanostructures is used to detect the concentration change of γ-Aminobutyric Acid (GABA). As for the gold-chitosan nanoshell, it is made by using chitosan nanoparticles crosslinking with sodium tripolyphosphate(TPP) for the first step to form the chitosan nanoparticles, which would be covered with the gold sequentially. The size of the fabricated product was around 100nm. Based on the method that the sulfur end of the MPA linked to gold can form the very strong S–Au bond, and the carboxyl group, the other end of the MPA, can easily absorb the GABA. GABA is the mainly inhibitory neurotransmitter in the mammalian central nervous system in the human body. It plays such significant role in reducing neuronal excitability throughout the nervous system. When the system formed, it generated SERS, which made a clear difference in the intensity of Raman scattering within the range of GABA concentration. So it is obtained from the experiment that the calibration curve according to the GABA concentration relevant with the SERS scattering. In this study, DLS, SEM, FT-IR, UV, SERS were used to analyze the products to obtain the conclusion.

Keywords: chitosan-gold nanoshell, mercaptopropionic acid, γ-aminobutyric acid, surface-enhanced Raman scattering

Procedia PDF Downloads 258

Authors: Zoltán Weltsch, József Hlinka, Eszter Kókai

Abstract:

The temperature dependence of wettability (wetting angle, Θ (T)) for Ag-based melts on graphite and Al2O3 substrates is compared. Typical alloying effects are found, as the Ag host metal is gradually replaced by various metallic elements. The essence of alloying lies in the change of the electron/atom (e/a) ratio. This ratio is also manifested in the shift of wetting angles on the same substrate. Nevertheless, the effects are partially smeared by other (metallurgical) factors, like the interaction between the oxygen-alloying elements and by the graphite substrate-oxygen interaction. In contrast, such effects are not pronounced in the case of Al2O3 substrates. As a consequence, Θ(T) exhibits an opposite trend in the case of two substrates. Crossovers of the Θ(T) curves were often found. The positions of crossovers depend on the chemical character and concentration of solute atoms. Segregation and epitaxial texture formation after solidification were also observed in certain alloy drops, especially in high concentration range. This phenomenon is not yet explained in every detail.

Keywords: contact angle, graphite, silver, soldering, solid solubility, substrate, temperature dependence, wetting

Procedia PDF Downloads 410

Authors: M. Budakoglu, M. Karaman, A. Abdelnasser, M. Kumral

Abstract:

The spatial interpolation and spatial correlation of the rare earth elements (REE) of lake surface sediments of Lake Acıgöl and its surrounding lithological units is carried out by using GIS techniques like Inverse Distance Weighted (IDW) and Geographically Weighted Regression (GWR) techniques. IDW technique which makes the spatial interpolation shows that the lithological units like Hayrettin Formation at north of Lake Acigol have high REE contents than lake sediments as well as ∑LREE and ∑HREE contents. However, Eu/Eu* values (based on chondrite-normalized REE pattern) show high value in some lake surface sediments than in lithological units and that refers to negative Eu-anomaly. Also, the spatial interpolation of the V/Cr ratio indicated that Acıgöl lithological units and lake sediments deposited in in oxic and dysoxic conditions. But, the spatial correlation is carried out by GWR technique. This technique shows high spatial correlation coefficient between ∑LREE and ∑HREE which is higher in the lithological units (Hayrettin Formation and Cameli Formation) than in the other lithological units and lake surface sediments. Also, the matching between REEs and Sc and Al refers to REE abundances of Lake Acıgöl sediments weathered from local bedrock around the lake.

Keywords: spatial geochemical modeling, IDW, GWR techniques, REE, lake sediments, Lake Acıgöl, Turkey

Procedia PDF Downloads 549

Authors: Abdul Qader Melhm, Hussein Elrafidi

Abstract:

This paper is dealing with studying the structural behavior of a steel-composite hollow reinforced concrete (RC) column model under combined eccentric loading. The composite model consists of an inner steel tube surrounded via a concrete core with longitudinal and circular transverse reinforcement. The radius of gyration according to American and Euro specifications be calculated, in order to calculate the thinnest ratio for this type of composite column model, in addition to the flexural rigidity. Formulas for interaction diagram is given for this type of model, which is a general loading conditions in which an element is exposed to an axial load with bending at the same time. The structural capacity of this model, elastic, plastic loads and strains will be computed and compared with experimental results. The total eccentric axial load of the column model is calculated based on the effective length KL available from several relationships provided in the paper. Furthermore, the inner tube experiences buckling failure after reaching its maximum strength will be investigated.

Keywords: column, composite, eccentric, inner tube, interaction, reinforcement

Procedia PDF Downloads 190

Authors: Ankita Jadon, Sidi Souvi, Nathalie Girault, Denis Petitprez

Abstract:

Safety requirements for Generation IV nuclear reactor designs, especially the new generation sodium-cooled fast reactors (SFR) require a risk-informed approach to model severe accidents (SA) and their consequences in case of outside release. In SFRs, aerosols are produced during a core disruptive accident when primary system sodium is ejected into the containment and burn in contact with the air; producing sodium aerosols. One of the key aspects of safety evaluation is the in-containment sodium aerosol behavior and their interaction with fission products. The study of the effects of sodium fires is essential for safety evaluation as the fire can both thermally damage the containment vessel and cause an overpressurization risk. Besides, during the fire, airborne fission product first dissolved in the primary sodium can be aerosolized or, as it can be the case for fission products, released under the gaseous form. The objective of this work is to study the interactions between sodium aerosols and fission products (Iodine, toxic and volatile, being the primary concern). Sodium fires resulting from an SA would produce aerosols consisting of sodium peroxides, hydroxides, carbonates, and bicarbonates. In addition to being toxic (in oxide form), this aerosol will then become radioactive. If such aerosols are leaked into the environment, they can pose a danger to the ecosystem. Depending on the chemical affinity of these chemical forms with fission products, the radiological consequences of an SA leading to containment leak tightness loss will also be affected. This work is split into two phases. Firstly, a method to theoretically understand the kinetics and thermodynamics of the heterogeneous reaction between sodium aerosols and fission products: I2 and HI are proposed. Ab-initio, density functional theory (DFT) calculations using Vienna ab-initio simulation package are carried out to develop an understanding of the surfaces of sodium carbonate (Na2CO3) aerosols and hence provide insight on its affinity towards iodine species. A comprehensive study of I2 and HI adsorption, as well as bicarbonate formation on the calculated lowest energy surface of Na2CO3, was performed which provided adsorption energies and description of the optimized configuration of adsorbate on the stable surface. Secondly, the heterogeneous reaction between (I2)g and Na2CO3 aerosols were investigated experimentally. To study this, (I2)g was generated by heating a permeation tube containing solid I2, and, passing it through a reaction chamber containing Na2CO3 aerosol deposit. The concentration of iodine was then measured at the exit of the reaction chamber. Preliminary observations indicate that there is an effective uptake of (I2)g on Na2CO3 surface, as suggested by our theoretical chemistry calculations. This work is the first step in addressing the gaps in knowledge of in-containment and atmospheric source term which are essential aspects of safety evaluation of SFR SA. In particular, this study is aimed to determine and characterize the radiological and chemical source term. These results will then provide useful insights for the developments of new models to be implemented in integrated computer simulation tool to analyze and evaluate SFR safety designs.

Keywords: iodine adsorption, sodium aerosols, sodium cooled reactor, DFT calculations, sodium carbonate

Procedia PDF Downloads 214

Authors: Uchenna Sydney Mbamara, Bolu Olofinjana, Ezekiel Oladele B. Ajayi

Abstract:

Elaborate surface metrology of undoped ZnO thin films, deposited by organometallic chemical vapour deposition (OMCVD) technique at different precursor flow rates, was carried out. Dicarbomethyl-zinc precursor was used. The films were deposited on AISI304L steel and soda-lime glass substrates. Ultraviolet-visible-near-infrared (UV-Vis-NIR) spectroscopy showed that all the thin films were over 80% transparent, with an average bandgap of 3.39 eV, X-ray diffraction (XRD) results showed that the thin films were crystalline with a hexagonal structure, while Rutherford backscattering spectroscopy (RBS) results identified the elements present in each thin film as zinc and oxygen in the ratio of 1:1. Microscope and contactless profilometer results gave images with characteristic colours. The profilometer also gave the surface roughness data in both 2D and 3D. The asperity distribution of the thin film surfaces was Gaussian, while the average fractal dimension Da was in the range of 2.5 ≤ Da. The metrology proved the surfaces good for ‘touch electronics’ and coating mechanical parts for low friction.

Keywords: undoped ZnO, precursor flow rate, OMCVD, thin films, surface texture, tribology

Procedia PDF Downloads 57

Authors: Jianxin Zhu, Na Liu

Abstract:

Entry strategies play a vital role in the development of new enterprises in the catering industry. Different entry strategies will have different effects on the development of new enterprise. Based on the research of scholars at home and abroad, and combining the characteristics of the catering industry, the entry strategies are divided into low-price entry strategies and high-quality entry strategies. Facing the entry of new enterprise, the strategies of incumbent enterprises are divided into response strategies and non-response strategies. This paper uses evolutionary game theory to study the strategic interaction mechanism between incumbent companies and new enterprises. When different initial values and parameter values are set, which strategy will the two-game subjects choose, respectively? Using matlab2016 for numerical simulation, the results show that the choice of strategies for new enterprise and incumbent enterprise is influenced by more than one factor, and the system has different evolution trends under different circumstances. When the parameters were set, the choice of two subjects' strategies mainly depends on the net profit between the strategies.

Keywords: catering industry, entry strategy, evolutionary game, strategic interaction mechanism

Procedia PDF Downloads 123

Authors: A. K. M. Kafi, S. N. Nina, Mashitah M. Yusoff

Abstract:

In this work, we have described a new 3-dimensional (3D) network of crosslinked Horseradish Peroxidase/Carbon Nanotube (HRP/CNT) on a thiol-modified Au surface in order to build up the effective electrical wiring of the enzyme units with the electrode. This was achieved by the electropolymerization of aniline-functionalized carbon nanotubes (CNTs) and 4-aminothiophenol -modified-HRP on a 4-aminothiophenol monolayer-modified Au electrode. The synthesized 3D HRP/CNT networks were characterized with cyclic voltammetry and amperometry, resulting the establishment direct electron transfer between the redox active unit of HRP and the Au surface. Electrochemical measurements reveal that the immobilized HRP exhibits high biological activity and stability and a quasi-reversible redox peak of the redox center of HRP was observed at about −0.355 and −0.275 V vs. Ag/AgCl. The electron transfer rate constant, KS and electron transfer co-efficient were found to be 0.57 s-1 and 0.42, respectively. Based on the electrocatalytic process by direct electrochemistry of HRP, a biosensor for detecting H2O2 was developed. The developed biosensor exhibits excellent electrocatalytic activity for the reduction of H2O2. The proposed biosensor modified with HRP/CNT 3D network displays a broader linear range and a lower detection limit for H2O2 determination. The linear range is from 1.0×10−7 to 1.2×10−4M with a detection limit of 2.2.0×10−8M at 3σ. Moreover, this biosensor exhibits very high sensitivity, good reproducibility and long-time stability. In summary, ease of fabrication, a low cost, fast response and high sensitivity are the main advantages of the new biosensor proposed in this study. These obvious advantages would really help for the real analytical applicability of the proposed biosensor.

Keywords: biosensor, nanomaterials, redox enzyme, thiol-modified Au surface

Procedia PDF Downloads 328

Authors: Shuxin Li, Peihao Song, Haixiao Hu, Dongfeng Cao

Abstract:

The interactive deformation and failure mechanisms, including local bucking/delamination propagation and global bucking, are investigated in this paper with numerical simulation and validation with experimental results. Three dimensional numerical models using ABAQUS brick elements combined with cohesive elements and contact elements are developed to simulate the deformation and failure characteristics of composite laminates with and without delamination under compressive loading. The zero-thickness cohesive elements are inserted on the possible path of delamination propagation, and the inter-laminate behavior is characterized by the mixed-mode traction-separation law. The numerical simulations identified the complex feature of interaction among local buckling and/or delamination propagation and final global bucking for composite laminates with delamination under compressive loading. Firstly there is an interaction between the local buckling and delamination propagation, i.e., local buckling induces delamination propagation, and then delamination growth further enhances the local buckling. Secondly, the interaction between the out-plan deformation caused by local buckling and the global bucking deformation results in final failure of the composite laminates. The simulation results are validated by the good agreement with the experimental results published in the literature. The numerical simulation validated with experimental results revealed that the degradation of the load capacity, in particular of the compressive strength of composite structures with delamination, is mainly attributed to the combined local buckling/delamination propagation effects. Consequently, a simple field-bolt repair approach that can hinder the local buckling and prevent delamination growth is explored. The analysis and simulation results demonstrated field-bolt repair could effectively restore compressive strength of composite laminates with delamination.

Keywords: cohesive elements, composite laminates, delamination, local and global bucking, field-bolt repair

Procedia PDF Downloads 116

Authors: P. Krachodnok

Abstract:

In this paper, the design of a multiple U-slotted microstrip patch antenna with frequency selective surface (FSS) as a superstrate for WLAN and WiMAX applications is presented. The proposed antenna is designed by using substrate FR4 having permittivity of 4.4 and air substrate. The characteristics of the antenna are designed and evaluated the performance of modelled antenna using CST Microwave studio. The proposed antenna dual resonant frequency has been achieved in the band of 2.37-2.55 GHz and 3.4-3.6 GHz. Because of the impact of FSS superstrate, it is found that the bandwidths have been improved from 6.12% to 7.35 % and 3.7% to 5.7% at resonant frequencies 2.45 GHz and 3.5 GHz, respectively. The maximum gain at the resonant frequency of 2.45 and 3.5 GHz are 9.3 and 11.33 dBi, respectively.

Keywords: multi-slotted antenna, microstrip patch antenna, frequency selective surface, artificial magnetic conduction

Procedia PDF Downloads 374

Authors: Youssef Wardeh, Elias Kinab, Pierre Rahme, Gilles Escadeillas, Stephane Ginestet

Abstract:

Urban heat islands designate a local phenomenon that appears in high density cities. This results in a rise ofambient temperature in the urban area compared to the neighboring rural area. Solar radiation plays an important role in this phenomenon since it is partially absorbed by the materials, especially roads and parking lots. Cool pavements constitute an innovative and promising technique to mitigate urban heat islands. The cool pavements studied in this work allow to limit the increase of the surface temperature, thanks to evaporation of the water conducted through capillary pores, from the humidified base to the surface exposed to solar radiation. However, the performance or the cooling capacity of a pavement sometimes remained difficult to characterize. In this work, a new definition of the cooling capacity of a pavement is presented, and a correlation between the latter and the hydrothermal properties of cool pavements is revealed. Firstly, several porous concrete pavements were characterized through their hydrothermal properties, which can be related to the cooling effect, such as albedo, thermal conductivity, water absorption, etc. Secondly, these pavements initially saturated and continuously supplied with water through their bases, were exposed to external solar radiation during three sunny summer days, and their surface temperatures were measured. For draining pavements, a strong second-degreepolynomial correlation(R² = 0.945) was found between the cooling capacity and the term, which reflects the interconnection of capillary water to the surface. Moreover, it was noticed that the cooling capacity reaches its maximum for an optimal range of capillary pores for which the capillary rise is stronger than gravity. For non-draining pavements, a good negative linear correlation (R² = 0.828) was obtained between the cooling capacity and the term, which expresses the ability to heat the capillary water by the energystored far from the surface, and, therefore, the dominance of the evaporation process by diffusion. The latest tests showed that this process is, however, likely to be disturbed by the material resistance to the water vapor diffusion.

Keywords: urban heat islands, cool pavement, cooling capacity, hydrothermal properties, evaporation

Procedia PDF Downloads 93

Authors: Gesti Prastiti, Maylina Adani, Yuyun darma A. N., M. Khilmi F., Yunita Wahyu Pratiwi

Abstract:

Combination therapy may allow interaction on two drugs or more that can give adverse effects on patients. Simvastatin is a drug of antihyperlipidemia it can interact with drugs which work on cytochrome P450 CYP3A4 because it can interfere the performance of simvastatin. Flavonoid found in plants can inhibit the cytochrome P450 CYP3A4 if taken with simvastatin and can increase simvastatin levels in the body and increases the potential side effects of simvastatin such as myopati and rhabdomyolysis. Green tea leaves and mint are herbal medicine which has the effect of antihiperlipidemia. This study aims to determine the potential interaction of simvastatin with herbal drinks (green tea leaves and mint). This research method are experimental post-test only control design. Test subjects were divided into 5 groups: normal group, negative control group, simvastatin group, a combination of green tea group and the combination group mint leaves. The study was conducted over 32 days and total cholesterol levels were analyzed by enzymatic colorimetric test method. Results of this study is the obtainment of average value of total cholesterol in each group, the normal group (65.92 mg/dL), the negative control group the average total cholesterol test in the normal group was (69.86 mg/dL), simvastatin group (58.96 mg/dL), the combination of green tea group (58.96 mg/dL), and the combination of mint leaves (63.68 mg/dL). The conclusion is between simvastatin combination therapy with herbal drinks have the potential for pharmacodynamic interactions with a synergistic effect, antagonist, and a powerful additive, so the combination therapy are no more effective than a single administration of simvastatin therapy.

Keywords: hyperlipidemia, simvastatin, herbal drinks, green tea leaves, mint leaves, drug interactions

Procedia PDF Downloads 392

Authors: Najla M. Salkho, Vinod Paul, Pierre Kawak, Rute F. Vitor, Ana M. Martin, Nahid Awad, Mohammad Al Sayah, Ghaleb A. Husseini

Abstract:

Liposomes are popular lipid bilayer nanoparticles that are highly efficient in encapsulating both hydrophilic and hydrophobic therapeutic drugs. Liposomes promote a low risk controlled release of the drug avoiding the side effects of the conventional chemotherapy. One of the great potentials of liposomes is the ability to attach a wide range of ligands to their surface producing ligand-mediated active targeting of cancer tumour with limited adverse off-target effects. Ultrasound can also aid in the controlled and specified release of the drug from the liposomes by breaking it apart and releasing the drug in the specific location where the ultrasound is applied. Our research focuses on the synthesis of PEGylated liposomes (contain poly-ethylene glycol) encapsulated with the model drug calcein and studying the effect of low frequency ultrasound applied at different power densities on calcein release. In addition, moieties are attached to the surface of the liposomes for specific targeting of the cancerous cells which over-express the receptors of these moieties, ultrasound is then applied and the release results are compared with the moiety free liposomes. The results showed that attaching these moieties to the surface of the PEGylated liposomes not only enhance their active targeting but also stimulate calcein release from these liposomes.

Keywords: active targeting, liposomes, moieties, ultrasound

Procedia PDF Downloads 597

Authors: Shajaratuldur Ismail, Nurlidia Mansor, Zakaria Man

Abstract:

Thermoplastic starch (TPS) plasticized by 1-ethyl-3-methylimidazolium acetate [Emim][OAc] were obtained through gelatinization process. The gelatinization process occurred in the presence of water and [Emim][OAc] as plasticizer at high temperature (90˚C). The influence of [Emim][OAc] and water on the gelatinization and interactions with starch have been studied over a range of compositions. The homogenous mass was obtained for the samples containing 35, 40 and 43.5 % of water contents which showed that water plays important role in gelatinization process. Detailed IR spectroscopy analysis showed decrease in hydrogen bonding intensity and strong interaction between acetate anion in [Emim][OAc] and starch hydroxyl groups in the presence of [Emim][OAc]. Starch-[Emim][OAc]-water mixture at 10-3-8.7 presented homogenous mass, less hydrogen bonding intensity and strong interaction between acetate anion in [Emim][OAc] and starch hydroxyl groups.

Keywords: starch, ionic liquid, 1-ethyl-3-methylimidazolium acetate, plasticizer, gelatinization, IR spectroscopy

Procedia PDF Downloads 226

Authors: Rashad Al-Gaashani

Abstract:

The physicochemical activation method was used to produce high-quality activated carbon (AC) with a large surface area of about 2000 m2/g from low-cost and abundant biomass wastes in Qatar, namely date seeds. X-Ray diffraction (XRD), scanning electron spectroscopy (SEM), energy dispersive X-Ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis was used to evaluate the AC samples. AC produced from date seeds has a wide range of pores available, including micro- and nano-pores. This type of AC with a well-developed pore structure may be very attractive for different applications, including air and water purification from micro and nano pollutants. Heavy metals iron (III) and copper (II) ions were removed from wastewater using the AC produced using a batch adsorption technique. The AC produced from date seeds biomass wastes shows high removal of heavy metals such as iron (III) ions (100%) and copper (II) ions (97.25%). The highest removal of copper (II) ions (100%) with AC produced from date seeds was found at pH 8, whereas the lowest removal (22.63%) occurred at pH 2. The effect of adsorption time, adsorbent dose, and pH on the removal of heavy metals was studied.

Keywords: activated carbon, date seeds, biomass, heavy metals removal, water treatment

Procedia PDF Downloads 72

Authors: Kuei-Hao Li, Eden Huang

Abstract:

Motivation suggests the willingness one person has towards taking action. Learners’ motivation has frequently been regarded as the most crucial factor in successful language acquisition. Without sufficient motivation, learners cannot achieve long-term learning goals despite remarkable abilities. Therefore, the study aims to investigate motivation of interaction tasks designed by the researchers for college EFL learners in Travel English class in virtual reality environment, integrating CUE model, Cognition, Usage and Expansion in the course. Thirty college learners were asked to join the virtual language learning website designed by the researchers. Data was collected via feedback questionnaire, interview, and learner interactions. The findings indicated that the course in the CUE model in language learning website of virtual reality environment was effective at motivating EFL learners and improving their oral communication and social interactions in the learning process. Some pedagogical implications are also provided in helping both language instructors and EFL learners in virtual reality environment.

Keywords: motivation, virtual reality, virtual language learning, second language acquisition

Procedia PDF Downloads 385

Authors: Utsav Swarnkar, Rabi Pathak, Rina Maiti

Abstract:

This study aims to investigate the thermoregulatory role of sweating by comprehensively analyzing the evaporation process and its thermal cooling impact on local skin temperature at various time intervals. Traditional experimental methods struggle to fully capture these intricate phenomena. Therefore, numerical simulations play a crucial role in assessing sweat production rates and associated thermal cooling. This research utilizes transient computational fluid dynamics (CFD) to enhance our understanding of the evaporative cooling process on human skin. We conducted a simulation employing the k-w SST turbulence model. This simulation includes a scenario where sweat evaporation occurs over the skin surface, and at particular time intervals, temperatures at different locations have been observed and its effect explained. During this study, sweat evaporation was monitored on the skin surface following the commencement of the simulation. Subsequent to the simulation, various observations were made regarding temperature fluctuations at specific points over time intervals. It was noted that points situated closer to the periphery of the droplets exhibited higher levels of heat transfer and lower temperatures, whereas points within the droplets displayed contrasting trends.

Keywords: CFD, sweat, evaporation, multiphase flow, local heat loss

Procedia PDF Downloads 59

Authors: Saad Bin Ismail, Muhammad Ateeq Qureshi, Rao Muhammad Zahid Khalil

Abstract:

In the last few decades, urbanization worldwide has been sprawled manifold, which is denunciated in the growth of urban infrastructure and transportation. Urban Heat Island (UHI) can induce deterioration of the living environment, disabilities, and rises in energy usages. In this study, the prevalence/presence of Surface Urban Heat Island (SUHI) effect in major cities of Pakistan, including Islamabad, Rawalpindi, Lahore, Karachi, Quetta, and Peshawar has been investigated. Landsat and SPOT satellite images were acquired for the assessment of urban sprawl. MODIS Land Surface Temperature product MOD11A2 was acquired between 1000-1200 hours (local time) for assessment of urban heat island. The results of urban sprawl informed that the extent of Islamabad and Rawalpindi urban area increased from 240 km2 to 624 km2 between 2000 and 2016, accounted 24 km2 per year, Lahore 29 km2, accounted 1.6 km2 per year, Karachi 261 km2, accounted for 16 km2/ per year, Peshawar 63 km2, accounted 4 km2/per year, and Quetta 76 km2/per year, accounted 5 km2/per year approximately. The average Surface Urban Heat Island (SUHI) magnitude is observed at a scale of 0.63 ᵒC for Islamabad and Rawalpindi, 1.25 ᵒC for Lahore, and 1.16 ᵒC for Karachi, which is 0.89 ᵒC for Quetta, and 1.08 ᵒC for Peshawar from 2000 to 2016. The pixel-based maximum SUHI intensity reaches up to about 11.40 ᵒC for Islamabad and Rawalpindi, 15.66 ᵒC for Lahore, 11.20 ᵒC for Karachi, 14.61 ᵒC for Quetta, and 15.22 ᵒC for Peshawar from the baseline of zero degrees Centigrade (ᵒC). The overall trend of SUHI in planned cities (e.g., Islamabad) is not found to increase significantly. Spatial and temporal patterns of SUHI for selected cities reveal heterogeneity and a unique pattern for each city. It is well recognized that SUHI intensity is modulated by land use/land cover patterns (due to their different surface properties and cooling rates), meteorological conditions, and anthropogenic activities. The study concluded that the selected cities (Islamabad, Rawalpindi, Lahore, Karachi, Quetta, and Peshawar) are examples where dense urban pockets observed about 15 ᵒC warmer than a nearby rural area.

Keywords: urban heat island , surface urban heat island , urbanization, anthropogenic source

Procedia PDF Downloads 319

Authors: Fatiha Aouabed, Abdelhafid Bayadi, Rabah Boudissa

Abstract:

Nowadays, silicone rubber insulation materials are widely used in high voltage outdoor insulation systems as they can combat pollution flashover problems. The difference in pollution flashover performance of silicone rubber and other insulating materials is due to the way that water wets their surfaces. It resides as discrete drops on silicone rubber, and the mechanism of flashover is due to the breakdown of the air between the water drops and the distortion of these drops in the direction of the electric field which brings the insulation to degradation and failure. The main objective of this work is to quantify the effect of different types of water drops arrangements, their position and dry bands width on the flashover voltage of the silicone insulating surface with non-uniform electric field systems. The tests were carried out on a rectangular sample under AC voltage. A rod-rod electrode system is used. The findings of this work indicate that the performance of the samples decreases with the presence of water drops on their surfaces. Further, these experimental findings show that there is a limiting number of rows from which the flashover voltage of the insulation is minimal and constant. This minimum is a function of the distance between two successive rows. Finally, it is concluded that the system withstand voltage increases when the row of droplets on the electrode axis is removed.

Keywords: contamination, flashover, testing, silicone rubber insulators, surface wettability, water droplets

Procedia PDF Downloads 440

Authors: Rio Hirakawa, Christian Gundlach, Sven Hartwig

Abstract:

Aluminium has been used in a wide range of industrial applications due to its numerous advantages, including excellent specific strength, thermal conductivity, corrosion resistance, workability and recyclability. The automotive industry is increasingly adopting multi-materials, including aluminium in structures and components to improve the mechanical usability and performance of individual components. A common method for assembling dissimilar materials is mechanical joining, but mechanical joining requires multiple manufacturing steps, affects the mechanical properties of the base material and increases the weight due to additional metal parts. Fusion bonding is being used in more and more industries as a way of avoiding the above drawbacks. Infusion bonding, and surface pre-treatment of the base material is essential to ensure the long-life durability of the joint. Laser surface treatment of aluminium has been shown to improve the durability of the joint by forming a passive oxide film and roughening the substrate surface. Infusion bonding, the polymer bonds directly to the metal instead of the adhesive, but the sensitivity to interfacial contamination is higher due to the chemical activity and molecular size of the polymer. Laser-treated surfaces are expected to absorb impurities from the storage atmosphere over time, but the effect of such changes in the treated surface over time on the durability of fusion-bonded joints has not yet been fully investigated. In this paper, the effect of the ageing of laser-treated surfaces of aluminum alloys on the corrosion resistance of fusion-bonded joints is therefore investigated. AlMg3 of 1.5 mm thickness was cut using a water-jet cutting machine, cleaned and degreased with isopropanol and surface pre-treated with a pulsed fiber laser at a wavelength of 1060 nm, maximum power of 70 W and repetition rate of 55 kHz. The aluminum surfaces were then stored in air for various periods of time and their corrosion resistance was assessed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). For the aluminum joints, induction heating was employed as the fusion bonding method and single-lap shear specimens were prepared. The corrosion resistance of the joints was assessed by measuring the lap shear strength before and after neutral salt spray. Cross-sectional observations by scanning electron microscopy (SEM) were also carried out to investigate changes in the microstructure of the bonded interface. Finally, the corrosion resistance of the surface and the joint were compared and the differences in the mechanisms of corrosion resistance enhancement between the two were discussed.

Keywords: laser surface treatment, pre-treatment, bonding, corrosion, durability, interface, automotive, aluminium alloys, joint, fusion bonding

Procedia PDF Downloads 74

Authors: Pedro M. A. Vitoriano, Tito. G. Amaral

Abstract:

Automated Optical Inspection (AOI) Systems are commonly used on Printed Circuit Boards (PCB) manufacturing. The use of this technology has been proven as highly efficient for process improvements and quality achievements. The correct extraction of the component for posterior analysis is a critical step of the AOI process. Nowadays, the Pattern Matching Algorithm is commonly used, although this algorithm requires extensive calculations and is time consuming. This paper will present an improved algorithm for the component localization process, with the capability of implementation in a parallel execution system.

Keywords: AOI, automated optical inspection, SMD, surface mounting devices, pattern matching, parallel execution

Procedia PDF Downloads 296

Authors: Panagiotis Kyratsis, Konstantinos Kakoulis

Abstract:

Nowadays, the rapid development of CAD systems’ programming environments results in the creation of multiple downstream applications, which are developed and becoming increasingly available. CAD based manufacturing simulations is gradually following the same trend. Drilling is the most popular hole-making process used in a variety of industries. A specially built piece of software that deals with the drilling kinematics is presented. The cutting forces are calculated based on the tool geometry, the cutting conditions and the tool/work piece materials. The results are verified by experimental work. Finally, the response surface methodology (RSM) is applied and mathematical models of the total thrust force and the thrust force developed because of the main cutting edges are proposed.

Keywords: CAD, application programming interface, response surface methodology, drilling, RSM

Procedia PDF Downloads 467

Authors: Rahul S. Raj

Abstract:

Electro-mechanical impedance technique is a recently developed non-destructive method for structural health monitoring. This system comprises of piezo electric patch, bonded to the structure using an adhesive/epoxy and electrically excited to determine the health of the component. The subjected electric field actuates the PZT patch harmonically and imparts a force on the host structure. The structural response thus produced by the host component is in the form of peaks and valleys which further shows the admittance signatures of the structure for the given excitation frequency. Adhesives have the capability to change the structural signatures, in EMI technique, by transforming conductance and susceptance signatures. The static approximation provide a justifiable result where adhesive bond lines are thin and stiff. The epoxy adhesive bonds limits design flexibility due to poor bond strengths, hence to enhance the performance of the joints, a new technique is developed for joining PZT, i.e. the alloy bonding technique. It is a metallic joining compound which contains many active elements including Titanium, that reacts with the tenacious surface films of the ceramic and composites to create excellent bonds. This alloy-based bonding technique will be used for better strain interaction and rigorous stress transfer between PZT patch and the host structure.

Keywords: EMI technique, conductance, susceptance, admittance, alloy bonding

Procedia PDF Downloads 117

Authors: Hannah Edwards, Femke T. A. Buisman-Pijlman, Adrian Esterman, Craig Phillips, Sandra Orgeig, Andrea Gordon

Abstract:

Mother-infant bonding is a term which refers to the early emotional connectedness between a mother and her infant. Strong mother-infant bonding promotes higher quality mother and infant interactions including prolonged breastfeeding, secure attachment and increased sensitive parenting and maternal responsiveness. Strengthening of all such interactions leads to improved social behavior, and emotional and cognitive development throughout childhood, adolescence and adulthood. The positive outcomes observed following strong mother-infant bonding emphasize the need to screen new mothers for disrupted mother-infant bonding, and in turn the need for a robust, valid tool to assess mother-infant bonding. A recent scoping review conducted by the research team identified four tools to assess mother-infant bonding, all of which employed self-rating scales. Thus, whilst these tools demonstrated both adequate validity and reliability, they rely on self-reported information from the mother. As such this may reflect a mother’s perception of bonding with their infant, rather than their actual behavior. Therefore, a new tool to assess mother-infant bonding has been developed. The Recorded Interaction Task (RIT) addresses shortcomings of previous tools by employing observational methods to assess bonding. The RIT focusses on the common interaction between mother and infant of changing a nappy, at the target age of 2-6 months, which is visually recorded and then later assessed. Thirteen maternal and seven infant behaviors are scored on the RIT Observation Scoring Sheet, and a final combined score of mother-infant bonding is determined. The aim of the current study was to assess the content validity and inter-rater reliability of the RIT. A panel of six experts with specialized expertise in bonding and infant behavior were consulted. Experts were provided with the RIT Observation Scoring Sheet, a visual recording of a nappy change interaction, and a feedback form. Experts scored the mother and infant interaction on the RIT Observation Scoring Sheet and completed the feedback form which collected their opinions on the validity of each item on the RIT Observation Scoring Sheet and the RIT as a whole. Twelve of the 20 items on the RIT Observation Scoring Sheet were scored ‘Valid’ by all (n=6) or most (n=5) experts. Two items received a ‘Not valid’ score from one expert. The remainder of the items received a mixture of ‘Valid’ and ‘Potentially Valid’ scores. Few changes were made to the RIT Observation Scoring Sheet following expert feedback, including rewording of items for clarity and the exclusion of an item focusing on behavior deemed not relevant for the target infant age. The overall ICC for single rater absolute agreement was 0.48 (95% CI 0.28 – 0.71). Experts (n=6) ratings were less consistent for infant behavior (ICC 0.27 (-0.01 – 0.82)) compared to mother behavior (ICC 0.55 (0.28 – 0.80)). Whilst previous tools employ self-report methods to assess mother-infant bonding, the RIT utilizes observational methods. The current study highlights adequate content validity and moderate inter-rater reliability of the RIT, supporting its use in future research. A convergent validity study comparing the RIT against an existing tool is currently being undertaken to confirm these results.

Keywords: content validity, inter-rater reliability, mother-infant bonding, observational tool, recorded interaction task

Procedia PDF Downloads 174

Authors: Pinki Sharma, Himanshu Joshi

Abstract:

Distillery spentwash contains high chemical oxygen demand (COD), biological oxygen demand (BOD), color, total dissolved solids (TDS) and other contaminants even after biological treatment. The effluent can’t be discharged as such in the surface water bodies or land without further treatment. Reverse osmosis (RO) treatment plants have been installed in many of the distilleries at tertiary level. But at most of the places these plants are not properly working due to high concentration of organic matter and other contaminants in biologically treated spentwash. To make the membrane treatment proven and reliable technology, proper pre-treatment is mandatory. In the present study, ultra-filtration (UF) as pre-treatment of RO at tertiary stage was performed. Operating parameters namely initial pH (pHo: 2–10), trans-membrane pressure (TMP: 4-20 bars) and temperature (T: 15- 43°C) used for conducting experiments with UF system. Experiments were optimized at different operating parameters in terms of COD, color, TDS and TOC removal by using response surface methodology (RSM) with central composite design. The results showed that removal of COD, color and TDS by 62%, 93.5% and 75.5%, with UF, respectively at optimized conditions with increased permeate flux from 17.5 l/m2/h (RO) to 38 l/m2/h (UF-RO). The performance of the RO system was greatly improved both in term of pollutant removal as well as water recovery.

Keywords: bio-digested distillery spentwash, reverse osmosis, response surface methodology, ultra-filtration

Procedia PDF Downloads 345

Authors: A. Hegazy, Ahmed Elsayed, Essam El Shenawy, N. Allam, Hala Handal, K. R. Mahmoud

Abstract:

Highly crystalline, TiO₂ pristine sub-10 nm anatase nanocrystals were fabricated at low temperatures by post hydrothermal treatment of the as-prepared TiO₂ nanoparticles. This treatment resulted in bandgap narrowing and increased photocurrent density value (3.8 mA/cm²) when this material was employed in water splitting systems. The achieved photocurrent values are among the highest reported ones so far for the fabricated nanoparticles at this low temperature. This might be explained by the increased surface defects of the prepared nanoparticles. It resulted in bandgap narrowing that was further investigated using positron annihilation experiments by measuring positron lifetime and Doppler broadening. Besides, homogeneous spherical TiO₂ nanoparticles were synthesized in large diameter and high surface area and the high percentage of (001) facet by sol-gel method using potassium persulfate (K₂S₂O₈) as an oxidizing agent. The fabricated particles exhibited high exposed surface area, high photoactivity and reduced band gap. Enhanced performance for water splitting applications was displayed by formed TiO₂ nanoparticles. Their morphological and structural properties were studied to optimize their synthesis parameters in an attempt to construct more applicable fuel cells in the industry for hydrogen fuel production.

Keywords: positron annihilation, solar energy, TiO2 nanoparticles, water splitting

Procedia PDF Downloads 139